Electric heat-alarm



No. 625,843. Patented May 30, I899.

' H. F. JONES.

ELECTRIC HEAT ALARM.

(Application filed July 29, 1898.)

( No Model.)

PT If WITNESSES UNITED STATES PATENT OFF C HOWARD FEILI) JONES, orWILSON, NORTH CAROLINA.

ELECTRIC HEAT-ALARM.

SPECIFICATION forming part of Letters Patent No. 625,843, dated May 30,18 99.

Application filed July 29, 1898.

To all whom it may concern.-

Be itknown that I, HOWARD FEILD JONES, acitizen of the United States,residing at Wilson,in the county of Wilson and State of North Carolina,have invented a new and useful Improvement in Electric Heat-Alarms, ofwhich the following is a specification.

I have provided a heat-alarm attachment to the well-known StandardMetallic Thermometer for use in tobacco-barns to warn the attendant ofinjurious changes in the temperature in curing tobacco in the leaf, andfor this purpose myimprovement is directed to a simple formof anelectrically-actuated bell attachment to the temperature-coil whereby analarm will be made should the curing heat become too high or too low.The greatest care and attention are required in the curing of tobaccolest it be scalded by the heat running up beyond the proper degree orthe leaf caused to run by the return of the sap into the leaf from thestem and splotch theleaf when the temperature has fallen too low. Fromthese causes a barn of fine tobacco maybe spoiled in ashort time. A goodcurer will know what heat the particular kind of leaf will bear incuring it and especially in the early stages of the cure. The generalpractice of curingtobacco in the barn requires an attendant for eachbarn, and he must enter the barn at all hours and frequently to examinethe thermometer, to attend the fires, and to observe the condition ofthe tobacco. Should he fall asleep from exhaustion, or fail to observethe condition of the tobacco, or make a mistake in observing andregulating the temperature, the consequences would probably be the lossof the whole cure. By using the heat-alarm which I have provided one mancan attend to several barns in which tobacco is being cured. His laboris greatly reduced. He can get rest and sleep. He is not required to gointo the hot barn except when he has warning of such necessity, and thiswarning renders it certain to keep the attendant timely advised that theheat is either too high or too low. It is important that the time ofwarning can be set to suit the different conditions of the cure. Thealarm attachment can be easily and quickly set at the points beyondwhich the Serial to. 687,192. (No model.)

temperature is not wanted to vary, as experience may determine with aparticular kind of leaf, or the duration under which the tobacco hasbeen undergoing cure.

In the accompanying drawings the heatalarm attachment is shown asapplied to the circumferential edge of the plate of glass by means ofmetallic spring-clips in direct electrical connection with a bell, andsuch plate supplements the dial to form a free seatway at any pointaround the dial for the attachment of the clip connections.

In the drawings, Figure 1 is a front View of a thermometer heat-alarmembracing myimprovement. Fig. 2 is asideview of the same; and Figs. 3and 4 show one of the spring-clips with its contact-point, Fig. 5showing the same contact and conducting-clip as applied to the edge ofthe glass plate.

The precise improvement as illustrated will be specifically pointed outin the claims concluding this specification.

A very cheap way of producing the instrument is to take thetemperature-coil from the thermometer now in general use, known as theStandard Metallic Thermometer, and fasten the coil to a dial 1,graduated from zero to 200, and fasten the needle or dialhand 2 to thecoil, so that the needle will be caused to sweep the arc of the dialgraduations by the action of the coil.

The temperature-coil, which is seen in dot= ted lines in Fig. 2, may ormay not be inclosed in a case but asuitable backing should be providedby whichto hang the instrument in the desired position in the barn.

The needle or dial-hand is tipped with platimom for the purpose ofmaking electricalcontact.

As seen in Figs. 1 and 2, a strong glass plate 3 of good quality ismounted or seated in front of and away from the dial upon four (more orless) studs or hangers 4, fixed to the case or frame and applied to thecircumferential edge of said plate, for a purpose which I will presentlystate.

From a galvanic battery 5 an insulated wire 6 extends to thethermometer, and this wire has two insulated flexible branches 7 and 8,each of which is provided with a spring clip or clamp adapted to befirmly clamped to the edge of the glass plate 3 and have each acontact-point 11, standing on the inner side of the plate in the path ofthe needle or dialhand. The third spring-clip 12 connects the dial-handand battery by a separate wire and is adapted to be clamped to aprojecting part of the case or to one of the studs 4, which support theglass plate. Mounted in this way the glass plate has a free edge 13 allaround it, which gives convenience for slipping on and clamping theretoat any point between the studs the spring-clips, and for this purposetwo of the flexible conducting branches 7 and 8 must be long enough tomake the attachment of the clips to any point in the circumference ofthe plate to which it is desired that the dial-hand shall make contactwith the clips, and thereby connect them in the circuit.

To complete the circuit, the spring-clip 12 is for convenience attachedto a supportingstud of the glass plate to make the dial-hand the otherpole of the battery through the coil. The contact-points of thespring-clips are of platinum and stand so as to be within the aredescribed by the point of the dial-hand. As, therefore, the temperaturecauses the hand or needle to move along its are, it must 'engage one ofthe clip contact-points, if moved through a sufficient arc, and make theelectrical contact, and thereby ring the bell 14, which is in thecircuit; but until such contact is made the circuit is not complete andthere can be no alarm. As the spring-clips are clamped to the edge ofthe plate on opposite sides of the dial-hand, the contact is made witheither clip, according as the temperature may rise or fall, and undereither condition ring the bell to give the notice of too great or toolow temperature.

clip 12 and the coil, while the other two springclips 10, havingcontact-points, are put in electrical circuit, the one to indicate toogreat heat and the other to indicate too little heat.

The seating edge of the glass for the clips I prefer to make circular;but it may be made many-sided so long as it affords a free way uponwhich to slip on the clamps of the circuit-making clips as a means ofsounding an alarm when the dial-hand comes in contact with the clips.

The clips may be of any construction that will provide a firm clamp anda contact-point; but a simple form of metal clamp composed of twospring-plates 15, one of which has the contact-point, will be found toanswer the purpose, the plate having the contact-point also having thebattery connection.

I claim as my improvement- 1. The combination with a dial-thermometerand its indicating needle or hand, of a glass plate forming a continuousfree circumferential edge, metal spring-clips each connected to thebattery-wire and having a contact-point and adapted to be slipped overand clamped upon the free edge of the glass plate to support thecontact-points in the path of the dial-hand and a spring-clip havingelectrical connection with the'dial-hand.

2. I11 a dial-thermometer, and in combination with the dial and itsindicating-hand, a

glass plate supplementingand separated from and independent of the dial,and supported by metallic studs, and metal springclips, two of which areclamped upon the edge of the glass plate and having contact-points, anda third clip clamped in electrical connection with the dial-h and,substantially as described.

HOWARD FEILD JONES. \Vitnesses:

JACOB O. HAAS, ED. T. PEOPLES.

